Total and partial digestibility of diets combining the starch sources of high degradability (dried cassava hulls) and low degradability (corn), with nitrogen sources of high (yeast) and low (cottonseed meal and meat and bone meal) degradability, in a 2 x 2 factorial arrangement, were evaluated. Four Holstein steers (334 kg) fitted with ruminal and duodenal cannulas, in a 4 x 4 Latin Square were used. Chromic oxide was used as a marker for drying matter flow. Interactions of starch and N sources on apparent digestibility coefficient (ADC) of crude protein (CP) and neutral detergent fiber (NDF) was detected. Diets of corn and yeast, cassava hulls and cottonseed meal + meat and bone meal showed higher ADC of CP than diets of corn and meat and bone meal and with cassava hulls and yeast. The diet of starch and N with high ruminal degradability showed lower value than others diets, that was not different. Ruminal digestion of NDF was higher when starch source was corn compared with cassava hulls. The highest digestion of starch was higher in diets with cassava hulls than in diets of corn, in all segments of digestive system. Negative values for ruminal digestion of CP to experimental diets were observed. The N source influenced ruminal and intestinal digestion of energy. The ruminal digestion was higher in diets with yeast e intestinal digestion was higher in diets with cottonseed meal + meat and bone meal.
cassava hulls dried; corn; cottonseed meal; meat and bone meal; synchronisation; yeast
